Various compounds with a fungicidal activity for agricultural and horticultural use are known as compounds having an amidino group on the phenyl ring. Many of these compounds have a substituent in the para position of the amidino group, and the substituent is bonded via a heteroatom (oxygen, sulfur, or nitrogen) (see Patent Documents 1 to 10). However, the fungicidal activity of these compounds is insufficient.
There is also reported a compound having a substituent in the above-mentioned para-position directly bonded to a carbon atom without a heteroatom (see Patent Document 11). However, the compound of Patent Document 11 shows an excellent fungicidal activity when used at a high concentration, but has an insufficient effect in practical use as an agricultural and horticultural agent (see Comparative Test 1, described later).
Generally, long-term use of fungicides has recently led to the emergence of drug-resistant fungi. Accordingly, control by conventional fungicides, such as benzimidazole agents, has become difficult. There is thus an urgent demand for the development of a new type of drug that has a fungicidal activity not only on drug-sensitive fungi, but also on drug-resistant fungi.